Ask a friend to choose a number between 1 and 63 and make a mental note of it without telling you.

Show each of the six cards in turn to your friend and ask them whether it contains your number.

Using this information and the cards it is possible to say what the number is.

For example your friend might choose the number 21.

This appears on three cards:
The one starting with a 4
The one starting with a 1
And the one starting with a 16.

That is interesting! 4+1+16 =21

Is this always the case?
Why?

If you would like to play this game at home, download and print off this word document

Many thanks to Igor Podlubny for the idea for this problem